Rotary surface broaching machine



July 12, 1938. w. A. HART ROTARY SURFACE BROACHING MACHINE Filed April 29, 1935 2 Sheets-Sheet 1 INVENTORY M'Zlz'am fil Hare:

A TTORNEYS 2 Sheets-Sheet 2 w. A. HAR T ROTARY SURFACE BROACHING MACHINE Filed April 29, 1935 INVENTOR. I H z'ZZz'am fi; Hart;

BY M Z/ ATTORNEYS.

July 12,1938.

, Patented July 12, 1938 ,UNITED *STATES zuzam PATENT OFFiCE lonial Broach Company,

Michigan a corporation of Application April 29, 1935, Serial No, 18,841"

'7 Claims.

My invention relates to method and means for broaching surfaces, and particularly to a machine and methods for accurately broaching surfaces through the progressive'advancement of 5 cutting teeth laterally across the face of the element to'be broached.

While broaching operations have been effected heretofore on surfaces, difficulty has been :experiencedv when'broaching surfaces of castings 1 because of the hard outer layer formed thereon. Because of this hard layer, the breach, when passed directly thereacross, becomes rapidly dulled and ineifectivel In the co-pending application of A. L. Nilsson, Serial No. 733,184, filed 15 June 30, 1934, a method and machine: for broach- 25 broaching tool, each revolution of which effects the cutting of the material from the work piece pro'gressivelyfrom the side across the face thereof. This is effected by mounting the broaching blades in such manner as to have the cutting edges '30 progressively advance from one side across the face of the work element. This is made possible by having the teeth'disposed on an arc of in-.

creasing radius relative to the center of the rotating tool supporting element. 35 Preferably, I provide a plurality of scraping blades following the broaching blades which span the broached surface to perform a final dressing operation thereon by machining off the teeth marks which may be made on the surface due to o the roughing operation. The machine is so constructed as to be provided with a movable work supporting table, one side of which may be unloaded and loaded while the other side is supporting the work in position to be broached.

; After the passing ofthe broaching teeth, which may occur during only a portion of the angular movement of the toolsupporting'element, the supporting table may be moved to have the loaded ,work piece disposed in the path of the- 50 broachlng teeth. In this manner, the broaching tool may continuously rotate and the work loaded and unloaded relative to the cutting teeth without stopping the machine. The-table may be so constructed as to have opposite faces of the 55 work piece advanced into position relative to the V panying drawings, wherein:

teeth ofoppositely disposed broaching tools which simultaneously pass overthe opposite faces of the work piece to machine both faces in parallel relation. The teeth may --be independently mounted on the-rotatable base or may be made 5 into groups and mounted in contiguous relation. Similarly, a machine may be constructed having oppositely presenting broaching tools with a work supporting table disposed therebetween on which separate work pieces may be mounted to be dis.- posed in the path of the cutting teeth, to have separate work pieces machined simultaneously.

Accordingly, the main objects of my invention are: to provide a method for machining surfaces of castings, or like work pieces, through the progressive advancement of broaching teeth laterally across a face thereof; to provide a rotatable element having a plurality of spirally disposed teeth for machining from an inner edge of a work piece across the surface thereof during the single rotation of the element; to dispose the teeth of a rotatable broaching tool in such manner asfto have them progressively extended slightly beyond the other in a position to advance across the face of a work element during the rotation of the tool; to provide aplurality of scraping blades following the roughing teeth ior finishing the surface previously roughed; to provide-a support for the work which has a loading and machining position to have one work piece removed and another installed during the time a third work piece is being shiftable to insert two work pieces in position to be machined each time the tools are rotated, and, in general, to provide a machine and method for surfacing the face of a work piece which is simple in construction, positive in operation and economical of manufacture.

Other objects and features of novelty of my invention will be specifically pointed out or vwill become apparent when referring, for a better understanding of my invention, to the following description, taken in conjunction with the accom- Figure 1 is a view, partly in section and. partly in elevation, of a machine my invention;

Fig. 2 is an end view of the machine illustrated in Fig. l;

Fig. 3 is an enlarged broken view of the broaching tool illustrated in Fig. 2;

Fig. 4 is a reduced view of a broachins tool, similar to that illustrated in Fig. 3, showing a modified form thereof;

Fig. 5 is an enlarged sectional view of the construction illustrated in Fig. 3 taken on the line H thereof;

Fig. 6 is a view of structure similar to that illustrated in Fig. 1, showing a further form which my invention may assume;

Fig. '7 is a plan view of the structure illustrated in Fig. 6, and k Fig. 8 is a view of the structure similar to that illustrated in Fig. 7 showing a modified form thereof.

Referring to Figs. 1, 2 and 3, I have illustrated a broaching machine comprising a base I havembodying features of ing a standard 2 thereon embodyingL a hollow portion 3 wherein a' motor 4 is mounted. A bearing 5 is provided in tha upper portion of the standard 2 in which a stub shaft 6 is supported for rotational movements. The stub shaft 6 supports a disc I having'aplurality of teeth 3 thereon of the worm wheel type which may be cut directly therein or which may be disposed on sections 9, as illustrated in the figure, and secured to the periphery of the disc I. The teeth I of the disc 1 mate with a worm II which is supported by a shaft I2 on which a sprocket I3 is mounted. A similar sprocket I4 is mountedon the shaft I! of the motor 4 and a chain I6 interconnects the sprockets i3 and It for driving the shaft I2 and,

teeth II are spirally disposed relative to the center of the disc. The teeth are formed in a plurality of blocks I8 which mate with each other and with faces disposed on a projection I8 provided on the face of the disc. Suitable ribs 2| brace and strengthen the projection I9 while screws 22 secure the plates I3 to the disc. When the discs are mounted on the plate, the teeth are spirally disposed to progressively advance out- 'wardly from the center of the disc to effect a progressive cutting operation.

Following the blocks I3, having the teeth II thereon, a plurality of scraping blades 23 are provided, secured to the face of the disc I by suitable screws 24.. The plurality of cutting edges 25 on the scraping blades are disposed normal to the cutting edges I! and are substantially of the same height. The. cutting edges 25 are employed to scrape any ridges'from the face of the work piece which may have been produced by the teeth H when advancing laterally thereacross. A projectio'n 26 retains the scraping blades'23 in flrm position on the face of the disc 1 and is trac dby suitable ribs 21, In Fig. 5, I have shown a section of the scraping blades to'illustrate the cutting edges "thereof. Such cuttinzedges are substantially the same height .for producing a smooth finish to the surface machined by the teeth II.

On the opposite end of the base I to that contalning the upright 2, I=haveprovided a support" disposed so that the finished work piece may be removed and a work piece to be machined loaded at the loading station during the time a third work piece is being machined. After the machining operation the table may be turned to have the work piece to be machined disposedat the machining station while the machined work piece maybe removed at the loading station.

I have illustrated the clamping mechanism as comprising a yoke 3I having aclamping screw 32 therein, which clamps the work piece to the face of the table 29. Adjustable stop elements 33 are provided on the table securable in a desired position by screws 34 for accurately locating theelements 33 relative to the teeth of the broachin tool. Lugs 35 are provided on the table 29, having a sloping surface 36 thereon which rides over a spring biased plunger 31 which plungerthereafter projects into an aperture 38 in the lug 35 for accurately locating the table 29 at the loading and machining stations. 6

It will be noticed from Figs. 2 and 3, that the roughing teeth I1 and the scraping teeth 25 cccupy only a portion of the face of the disc I.

After the scraping teeth 25 have passed over the surface of the work piece, the table .may be rotated, without interfering with the teeth I I, to advance a work piece to be machined into the machining station during the rotation of the disc l before the roughing teeth II have been advanced to engage the work piece. By the time this has been accomplished, the first of the series of teeth II will have been advanced into a position to begin a cutting operation on the work element.

The work piece, herein designated at 30, may be a casting of any size. or proportion and is illustrated as being the block of an automotive vehicle engine. It will be understood that the size of machine will conform to the size of the work piece and that suitable clamps and post.- tioning elements will be employed on the table 29 to accurately locate and clamp the work pieces relative to the teeth of the breaching tools.

In Fig. 4 I have shown a further form which my cutting tool may assume that wherein the disc I has a base 4| mounted thereon on which a plurality of individual blades 42 are secured by 7 screws 43. These blades are radially positioned ting edgewill cut on an arc slightly beyond the arc machined by the cutting edge disposed in front thereof, and in this manner, progressively cut across the face of a work element. The teeth will begin cutting on the sides of the work piece and will progressively advance thereacross to machine the face of the element without directly attacking the hard face surface thereof, as has been attempted in the past. "In the present arrangement the teeth are not damaged by. ein advanced into a ,hard surface of a casting since the lateral advancement of the cutting edges causes the hard surface to crackandcrumble away without resistingthe cutting edges; In case the first of teeth are eventually damaged by initially attacking the rough the side of the casting, these can bereadily renewed.

After all of the'blada 2 have passed laterally across of the work piece a plurality of the scrsninsblades II are provided for the phlned-surfscebfthe work piece made by the teeth I. It '1]! b6 three-quarters I -purposeofdressingthecutmarksfromthcma-- A further extension of my inventive concept is illustrated in Figs. 6 and '7, wherein a base 45 is provided with two spaced upright standards 46, each of which is provided with a bearing for supporting a shaft 6 and disc I for rotation. The

discs I are the same as those heretofore described, being provided with broaching teeth I! on the inner faces and the driving teeth 8 on the peripheral edge. The teeth 8 of the discs are connected with a worm ii, the shaft of which is provided with a sprocket is interconnected by chains it to sprockets M on the shaft of the motor 4. The motor is mounted on a base 65 between the standards M and is also employed to drive a gear d! in engagement with rack teeth 58 provided on the underside of a table 49.

The table supports the work pieces 5i and is mounted in ways 52 for movement in reciprocation between the discs 'i.. A suitable reduction gear unit and clutch 53 controls the operation of the table in reciprocation relative to the position of the cutting edges on the discs i; that is to say, after the work pieces 5| have been machined, a space is provided on the face of the discs having no cutting teeth, which permits the work to be moved relative tothe discs faces to remove the finished work pieces and to insert new work pieces into position to be machined.

" This is accomplished before the teeth again reach a position to engage the work pieces.

The work pieces 5| are clamped upon the table 49 in any suitable manner, herein illustrated as being secured by a bar 53 which is forced down upon the work piece 5| by a bolt 54. Two of such holders are provided on the work carrying table 49, as illustrated in Fig. 7. The holders are mounted to have one set of work pieces in position to be machined, while the other set is in a loading position, so that the finished work pieces may be removed and new work pieces clamped in position during .the time another set of work pieces is being machined. After the machining operation, the table 49 is shifted to have the finished work pieces moved to a loading position while the work pieces, which were secured to the table during the prior machining operation, are moved into machining position.

It is within the purview of my invention to have the table 49 reduced in width and have the discs I disposed closer together to engage opposite sides of a single work piece M to machine both sides at the same time to exact parallelism and the .work piece to exact length. The machine will operate in the same manner as above described, which operation is continuous, theloading and unloading being efiected during the time the discs are turning after a machining operation and before the teeth are in position to again machine the work pieces.

In Fig. 8, I have shown a further form which my invention may assume, that wherein .the base 45, the discs I and driving mechanism are the same as that of the structure illustratedv in Figs. 6 and 7, with the exception that a work supporting table 56 is of the rotating, rather than the reciprocating, type. The work pieces 5| are clamped on thetable by arms 51 which are forced down thereon by the action of the clamping screws 58. As the discs 5 are rotating between the time the work pieces 5| are finished and before a machining operation is begun, the table 56 is rotated 90 degrees to advance new work pieces to machining position and to move the finished work pieces to the loading stations.

While this construction may be employed to finish two work pieces simultaneously, it may also be employed to advance the work pieces through diiferent machining stages to have a work piece at the point 59 disposed to be rough machined and thereafter to be advanced to the position 6| where a finishing operation may be eflected.' In this arrangement, a single loading station 62 will be provided which may be manned by a single operator. -When the work pieces 5! are roughed and finish machined in a single operation at the points 59 and BI, two operators will be required, one at the point 62 and the other at the position 63. Suitable guards 64 are provided for protecting the operation at the last mentioned from the teeth on the discs i. Suitable mechanism may be employed, interconnected with the motor 4 and the table 56 for eifecting the turning of the table 90 degrees immediately after a machining operation and before the teeth are in a position to again-machine a work piece.

ment of the table when the teeth are adiacent to the work piece, which wouldcause damage The advancement of the table 55 in this manner is desirable to prevent the move+- While I have described and illustrated several I embodimentsof my invention, it will be apparent to those skilled in the art that various changes,

omissions, additions and substitutions may be made therein without departing from the spirit and scopeoi my invention, as set forth in the accompanying claims.

' I claim as my invention:

1. A broaching tool comprising a disc mounted for rotation about its center, a plurality of teeth on said disc having cutting edges lying in substantially the same plane progressively projecting outfor rotation about its center, a plurality of teeth on said disc having cutting edges lying in substantially the same plane and progressively projecting outwardly toward the periphery of the .disc, means for positioning a work piece relative to said teeth, means for clamping said work, and means for rotating said disc to cause said teeth lying iii the same plane to progressively machine across the face of the work piece.

3. A broaching tool, including, in combination, a disc, a spiral row of broaching teeth disposed on said disc in substantially the same plane, and additional teeth extending between the center and the periphery of the disc for machining the surface cut by said teeth.

4. A broaching tool, including, in combination, a disc, a spiral row of broaching teeth disposed on 'iflld disc in substantially the same plane addi- 5. A broaching tool, including, in combination, a disc, a spiral row on breaching teeth disposed on said disc in substantially the same plane for progressively cutting during the rotation of the disc, a plurality oi blades of a width to span theprogressively extended outwardly from each otherv towards the periphery of said disc, and means for moving a work piece in position to be machined during the rotation of said disc.

7. A broaching machine for surfacing a work piece including, in combination, a rotatable disc, means for driving said disc, a plurality of cutting teeth on said disc having cutting edges lying in' substantially the same plane and progressively extended outwardly from each other towardsthe peripheries oi the disc, said teeth being provided 7 over a portion only of the face 01' the disc, a support for the worl: piece, means for locating and clamping the work piece on the support, and.

means for advancing the work element into machiming position while the disc surface having no teeth thereon is passing said position.

A. HART. 

